DEV C++ 错误：'}' 标记前的预期声明
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DEV C ++ Error: expected declaration before '}' token
提问by Francesca
What does this mean? My program goes like this: (NOTE: The line that has the error was the line coming before case 2.)
这是什么意思？我的程序是这样的：（注意：有错误的那一行是第 2 种情况之前的那一行。）
case 1:
{
cout<< "C * H * E * M * I * S * T * R * Y \n\n";
cout<< "1) What is the valence electron configuration of Selenium (Se)?\n\n";
cout<< "\na) 1s2 2s2 2p6 3s2\n\n";
cout<< "\nb) 1s2 2s2 2p2\n\n";
cout<< "\nc)4s2 4p4\n\n";
cout<< "\nd) 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5\n\n";
cout<< "Enter your answer:\n";
cin>> answer;
if (answer == 'c')
{
cout<<"Your answer is correct. Please press the enter key to proceed to the next question.\n\n";
}
else
cout<< "The correct answer is C. Please press the enter key to proceed to the next question.\n\n";
getch ();
}
getch ();
cout<< "2) Which element yields the biggest atomic radius?\n\n";
cout<< "\na) Ca\n\n";
cout<< "\nb) Xe\n\n";
cout<< "\nc) B\n\n";
cout<< "\nd) Cs\n\n";
cout<< "Enter your answer:\n";
cin>> answer;
if (answer == 'd')
{
cout<< "Your answer is correct. Please press the enter key to proceed to the next question.\n\n";
}
else
cout<< "The correct answer is D. Please press the enter key to proceed to the next question.\n\n";
getch ();
}
cout<< "3) Name the ionic compound K2 Cr2 O7\n\n";
cout<< "\na) potassium chloride\n\n";
cout<< "\nb) potassium carbonate\n\n";
cout<< "\nc) potassium chromite\n\n";
cout<< "\nd) potassium chromate\n\n";
cout<< "Enter your answer:\n";
cin>> answer;
if (answer == 'd')
{
cout<< "Your answer is correct. Please press the enter key to proceed to the next question.\n\n";
}
else
cout<< "The correct answer is D. Please press the enter key to proceed to the next question.\n\n";
getch ();
}
}
case 2:
{
cout<< "G * E * O * M * E * T * R * Y \n\n";
The error, as noted in the title is expected declaration before '}' tokenat the line noted in my opening paragraph.
标题中指出的错误expected declaration before '}' token位于我开头段落中指出的行中。
回答by Tim Post
I think you want this:
我想你想要这个：
if (answer == 'd')
{
cout<< "Your answer is correct. Please press the enter key to proceed to the next question.\n\n";
}
else
cout<< "The correct answer is D. Please press the enter key to proceed to the next question.\n\n";
getch ();
}
}
To look like this:
看起来像这样：
if (answer == 'd')
{
cout<< "Your answer is correct. Please press the enter key to proceed to the next question.\n\n";
} else {
cout<< "The correct answer is D. Please press the enter key to proceed to the next question.\n\n";
getch ();
}
It looks like you lost track of your scope immediately following the else.
看起来您在else.
回答by Bo Persson
There are two }'s right before the case. Where are the corresponding {'s? Especially the last elselooks a bit lonely.
之前有两个} case。对应的 { 在哪里？尤其是最后一张，else显得有些落寞。
回答by sarnold
After I reformatted your code so it would display tolerably on the website, the errors stand out pretty clearly.
在我重新格式化您的代码以便它可以在网站上正常显示后，错误非常明显。
I would recommend, when you use brackets around the ifclause, also use them around the elseclause:
我建议，当您在if子句周围使用括号时，也要在else子句周围使用它们：
if (foo) {
/* ... */
} else {
/* ... */
}
Leaving off the brackets is quite fine if both cases are just one statement. And while there's no requirement about putting brackets around both clauses if only one needsthem, I have found plenty of bugs around ifstatements with brackets around only one path. It's surprising. :)
如果两种情况都只是一个陈述，则省略括号是很好的。虽然如果只有一个人需要它们，则没有要求在两个子句周围都放置括号，但我发现了很多if围绕仅在一条路径周围带有括号的语句的错误。令人惊讶。:)
On a further note, a text editor with bracket-matching capabilities would be a huge assistance. Many editors will highlight brackets that aren't properly nested, and some provide a key to jump between them quickly. (In viand clones, the %key will bounce between (), {}, []and <>pairs. Very handy.)
进一步说明，具有括号匹配功能的文本编辑器将是一个巨大的帮助。许多编辑器会突出显示未正确嵌套的括号，有些编辑器提供了在它们之间快速跳转的键。（在vi和克隆，该%键会之间反弹()，{}，[]和<>对，非常方便。）
回答by Yury
Seems you have a superflous "}" after each getch:
每次获取后，您似乎都有一个多余的“}”：
getch ();
}
^^^
